Electric motor.



J. D. TAYLOR.

ELECTRIC MOTOR.

APPLICATION FILED MAILB, 1912.

Patented July 7 INVg TOR WITNESSES UNITED STATES PATENT OFFICE.

JOHN TAYLOR, OF EDO-EWOOD PARK, BE NNS YLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

' ELECTRIC moron.

To all whom it may Concern Belt known that 1, JOHN citizen of the United States, residing at Edgewood Park, in the county of Allegheny 5 and State of Pennsylvania, have invented 1O tric motors of the oscillating type.

A motor embodying my invention is par- 'ticularly adapted for the operation of electric bells, although. its use is not limited to this adaptation.

I willdescribe two forms of motor embodying my invention and-then point out the novel features thereof in claims.

In the accompanying drawings, Figure 1 is a plan View showing one form of electric 2ov motor embodying my invention, and showing its application to a bell. Fig.2 is a sectional view on the line II-II of Fig. 1, but showing the oscillating member in a slightly different position. ;Fig. 3 is a view 25 showing a modified form of motor embodying my invention. Figs. 4 and 5 are views similar to Fig. 3 but showing the oscillating member at different points in its movement.

Similar reference characters refer to similar' parts n each of the several views.

One feature of the motor embodying my invention is the absence of contacts or cominutator of any kind.

Referring to Figs. 1 and 2 of the accompanying drawings, 1 designates a field member built up of laminated soft iron and comprising four inwardly projecting poles 2, 3, 4, and 5. This field is supported on four posts 50, 51,52 and 53, which in turn are mounted in a base plate 18. 31 is an oscillating member, which may be termed an oscillator and which is also built up. of

laminated soft iron. This oscillator is fixed on a shaft 16 which is pivotally mounted 'n a lug 19 on the plate'18 and in a cross ar 19 mounted on the tops of posts 51 and ./53. In Fig. 1 the middle portion of this cross bar is broken away to more clearly show the oscillator 31. Passing through the oscillator 31 are four rods 12, 13, 14.- and 15 of conducting material preferably copper. These rods are located substantially ninety Specification of Letters Patent. 5

Application filed March 8', 1912. Serial No. 682,343.

D. .TAYLOR, a

Patented July 7, 1914.

degrees apart and are all electrically connected on each side of the oscillator'by means of plates 24 and 25 of conducting material, preferably of copper, thereby forming a structure similar to the squirrelcage rotor of an induction motor. Field poles 2 and 4 are provided with exciting coils 6 and 7 respectively; poles 3 and 5 have no exciting coils, but they provide a' mag netic path for flux produced by current induced in the circuit comprising thecopper rods 12 and 14 and the plates 2% and 25, as will hereinafter be explained. 20 is a block of insulating material such as wood secured to the base plate 18. This block carries terminal posts 22 and 23 to which the coils 6 and 7 are connected by means of conductors 54, and 56. Coils 6 and"? are supplied with alternating current from-a source which is connected with the terminal posts 22 and 23 by conductors 61 and 62, a circuit controller 63 being included in conductor 62 for controlling the bell.

, The modified form of motor shown in Fig. 3 is similar to that slown in Figs. 1 and 2,

except that rods 13 and 15 are omitted from the oscillator, which I have here designated 31, and pole-pieces 3 and 5 are omitted from the field, which I have here designated 1.

I will first explain the operation of the form of motor shown in Fig. 3, referring also to Figs. 4 and 5 which show the oscillator 31 in different positions of its movement.

Assume that the oscillator 31 occupies the position in which it is shown in Fig, 3, and that alternating currentis then supplied to the coils 6 and 7. The .closed'electric circuit comprising rods 12 and'14 then tends to place itself in such position that its plane is parallel to the direction of the magneto-mo tive forcebetween pole-pieces 2 and 4, this being the position in which it is shown in Fig. t, which I will term the middle. position; this is in accordance with the welllmown law that a closed circuit in a field of alternating magnetic flux tends to place itself in such position that none of the flux passes through it. i The force thus acting on the oscillator maybe termed the transformer torque. If the torque just mentioned were the only one tending to produce mot-ion of the oscillator, even though the momentum would carry the oscillator beyond the middle position and it would then be drawn back toward the middle position by a similar torque, the oscillations would soon cease because the torques on each side of the middle position are equal and opposite. The actionwould-be analo= gous to that of a pendulum having a fixed axis of suspension; such a pendulum will, when started, oscillate for a time, but the amplitude of oscillation will gradually deflows through the circuit comprising the rods 12 and 14, and which combines with the primary flux to form a resultant flux. The speed current coacts with this resultant flux to produce a torque which tends to continue "the movement of the oscillator beyond its middle position. The force thus acting on the oscillator may be termed the speed torque. The combined action of this last torque and of the torque tending to place the oscillator in its middle position makes the device analogous to a pendulum having a movable axis of suspension; if the axis-of such a pendulum .is moved by external agency at each oscillation and in the direction of movement of the pendulum, the 0scillations will continue indefinitely. After the oscillator 31 passes the middle position the. positionshown 'inFig. 4) the trans ormer torque, tending to return the oscillator to the middle position, acts in opposition to the speed torque and to the momentum, and when the oscillator reaches the point at which the transformer torque balances the two latter forces, the oscillator stops and the actions just described are repeated in the other direction. Of course, if any other force, such as gravity or a spring is acting on the oscillator, thISOthBI force must be added to or subtracted from the sum of the speed torque and the momentum in determiningthe point at which the oscillation will stop. In order words, the oscillation stops when the transformer action balances all other forces acting on the oscillator. In order to prevent continuous rotation, the parts of the device must be so proportioned that the balancing of the torques occurs before the oscillator reaches such a point that the trans former torque would tend to continue the rotation in the counter-clockwise direction. Obviously, with the form of motor shown in Figs. 3, 4 and 5 the parts must be so proportioned' that this balancing occurs before the oscillator swings 90 in either direction from its middle position, and this proportioning involves chiefly, and probably only,

the proper relative length of arc of the olefaces and of the spaces between poleaces. One reason for this is that while the rods 12 and 1 1 are opposite the pole-pieces, the transformer torque is always less than the speed torque, hence the length of the pole-- faces must be such that after the rods pass from under them the transformer torque can balance the other two torques before the oscillator has swung too far. One important feature of-my invention lies, therefore, in the proper proportioning of these arcs.

Referring now to Figs. 1 and 2, in the formof motor shown, the same actions occur as in the form shown in Fig. 3, with an additional speed torque. which renders the .motor more etlicient. Assuming that the oscillator is in the position shown in Fig. 1, when the alternating current is "applied, the circuit including rods 12 and 14 tends to place itself parallel to the direction offlux between pole-pieces 2 and 1 for the same'reason as before. "The circuit includ ing rods 13 and 15 also tends to place itself in a likeposition, but the tendency of the former circuit exceeds that of the latter because the former circuit is nearer this positionthan the latter. (This tendency is really due to the flux which passes around the circuit without passing through it, and obviously more flux can pass around the circuit comprising rods 12. and 14 than around that comprising rods 13 and 15.) The movement of rods'12 and '14 across the flux induces a speed current in the circuit of these rods as before, and this current sets up a speed flux as before, but in the structure of Fi 1 there is a ath of low reluctance for t is fiux throug the pole-Pieces 3 and 5 and the field 1. The primary flux between pole-pieces 2 and 4 also induces current in the circuit comprising rods 13 and 15, and this current coacts with the speed the transformer torque tending to return the circuit of rods 12 and 14' to the middle position. \Vith the structure shown in Fig. 1 this balancing must occur before the oscil- .lator has swungh 15 from its middle posi-- tionQbeca-use o erwise the circuit of rods 13 and 15 wouldbecome more nearly paral lel to the direction of the primary flux than v the circuit of rods 12'and 14, and continuous rotation would result. Here again oscillation depends on the proper proportioning of the parts, and this proportioning involves. chiefly, and probably only, the relative lengths of arc of pole-face and of space between pole-faces.

As mentioned hereinbefore, a motor .embodying my invention is adapted for the operation of a'bell. In Figs. land 2 I have shown a bell. 21 mounted upon the base 18. Secured to the oscillator shaft 16 is a collar 57 which carries a clapper 17 arranged to strike the bell when the oscillator is actuated. The entire structure including motor and bell is preferably mounted in the position shown in Figs. 1 and 2 in which the motor is below the bell, so that when the motor is deenergized the clapper 17 will hang awa' fr'onithe bell by gravity. The downwa-r; movement-of the clapper and armature may then be limited by means of a suitable stop 58 as indicated in Fig. l. The rate of oscillation of the oscillator is entirely independent of the frequency of the alternating current supplied to the motor winding, and is dependent only 9n the energysupplied and on the inertia of the oscillating parts. With the form of motor shown in Figs. 1 and 2, in order to have the oscillations start in the proper quadrant it is necessary that when the motor is at rest the planeof rods 12 and 14 should make a smaller angle with the direction of the priby the electromagnetic forces without the use of mechanical stops, and I have also found that a mechanical stop limiting the swing to one side of the middle position also limits the swing to the other side. In Fig.

, l thefstop 58 and bell 21 are so'located relative to the middle position of the oscillator limit of its stroke. i

' eration.

31 that the downward movement of the clapper is limitedby the electromagnetic forces and the clapper therefore does not strike the stop 58 while the motor is in op- By this arrangement I avoid the damping effect which-would result if the stop 58 were so located as to be struck by the clapper. In other words, the gong is so located as to be struck by the clapper when the latter is just reaching the upper I have found that if, while the motor is at rest, the angle between the direction of flux and the plane of rods 12 and 14 is very small, the oscillations at the start will be of small amplitude but will Having thus described my invention, what I I claim is.

1. An electric motor comprising an oscillator having a closed electric circuit, and means for passing alternating magnetic flux through said oscillator, whereby a trans former torque is exerted on said circuit which tends to swing the oscillator to a middle position in which none of said flux passes through said circuit and whereby the current induced in said circuit by its motion through the flux reacts on said flux to produce a speed torque which tends to continue the movement of the oscillator beyond said" middle position, the parts being so proportioned that after the oscillator has swung beyond said middle position the revcrsed transformer torque tending to return it to the middle position balances the sum of the speed torque, the momentum'and all other forces before 'the oscillator reaches such position that the transformer torque again reverses and tends to continue the rotation.

2. An electric motor comprising an oscillator having a closed electric circuit, means for passing alternating magnetic flux through said oscillator, means for biasing said oscillator to such position that a portion of said fiuX passes through said circuit, whereby a transformer torque is exerted on said circuit which tends to swing the oscillator to a middle position in which none of said flux passes through said circuit, and

whereby the current induced in said circuit by the motion of the circuit through the flux reacts on said flux to produce a speed torque which tends to continue the move-.

ment of the oscillator beyond said middle position, the parts being so proportionedthat afterthe oscillator has swung beyond said middle position the reversed transformer torque tending to return it to the middle position balances the sum of the speed torque, the momentum and the biasing means before the oscillator reaches such position that the transformer torque again reverses and tends to continue the rotation.

3. An electric motor comprising an alternating current elcctromagnet, an oscillator mounted between the pole pieces of said magnet and having a'closed electric cir'- -cuit whereby the flux passing through said 4. An electric'motor comprisin a field member of magnetizable materia having four inwardly rojecting pole-pieces disposed sub'stantia l in quadrature, windings on an oppositely ocated pair of said polepieces, for passing alternating magnetic flux etween the last-mentioned pole-pieces, an oscillator mounted between said pole-pieces and comprising a core of magnetizable material having two closed electric circuits disposed substantially in quadrature relation,

\- means for biasing said oscillator to such position that the plane of one of said closed circuits makes a smaller angle with the direction of theflsaid flux than does the plane of the other circuit, whereby the transformer torque exerted on said circuits by said flux acts to swing the oscillator to. a

'middle position which none of the said flux passes through the first-mentioned' closed circuit, and whereby the speed current induced in said first-mentioned circuit causes an alternating magnetic flux to fiow through the oscillator and the two polepieces not provided with windings, which flux reacts on the transformer current induced inthe second of said closed circuits to produce a speed torque which tends to continue the movement of the oscillator beyond said middle osition, the parts being so proportioned t at before the oscillator 'has swung forty-five degrees from'said middle position the reverse transformer torque tending to return the oscillator to the said middle position balances the said speed torque and the momentum and the said biaslng torque.

In testi'mon whereof I aflix my signature in presence 0 two witnesses.

- JOHN D. TAYLOR.

Witnesses:

WILLIAM H. CADWALLADEB, I L. Fnaonmc HOWARD. 

